The present invention relates in a general manner to auxiliary trip devices designed to be associated with circuit breakers, notably molded case circuit breakers.
A conventional molded case circuit breaker comprises in a general manner, inside a molded case, a circuit breaker operating mechanism, a trip bar movable in such a way as to bring about breaking of the latching of the circuit breaker operating mechanism and at least one main trip device designed to command movement of the trip bar. If the circuit breaker is multipole, a certain number of main trip devices may be provided, this number being equal to the number of poles of the circuit breaker. In this case, if any one of the main trip devices of the circuit breaker detects an electrical condition which is greater than a preset threshold, for example if it detects a current intensity flowing in the corresponding pole greater than a preset value, this main trip device operates to command movement of the trip bar, this movement of the trip bar causing breaking of the circuit breaker operating mechanism latching, and this circuit breaker operating mechanism thus causing simultaneous interruption of the different current channels which correspond to the different poles of the multipole circuit breaker.
In a conventional molded case circuit breaker of this kind, whether single-pole or multipole, it may be desirable to associate an auxiliary trip device to the circuit breaker, this trip device being designed to also be able to bring about breaking of the circuit breaker operating mechanism latching, independently from operation of the main trip device or devices included in the circuit breaker. For example, it may be desirable to associate or to combine with the circuit breaker an auxiliary trip device of a first type which performs continuous detection of the presence or absence of a voltage at circuit breaker level and which is designed to make the circuit breaker trip when this voltage falls to zero or falls below a preset threshold. Such an auxiliary trip device of this first type, which is a conventional auxiliary trip device, is commonly called "auxiliary trip device of the undervoltage release type".
An auxiliary trip device of a second type can also be used which is designed to make the circuit breaker trip when an electrical current greater than a preset level flows inside the auxiliary trip device. Such an auxiliary trip device of the second type, which is a conventional auxiliary trip device, is commonly called "auxiliary trip device of the shunt release type".
Consequently, circuit breakers including or receiving auxiliary trip devices which may be either auxiliary trip devices of the undervoltage release type or auxiliary trip devices of the shunt release type have already been achieved or proposed. It has also been proposed to design an auxiliary trip device able to constitute either an auxiliary trip device of the undervoltage release type or an auxiliary trip device of the shunt release type. An auxiliary trip device of this kind generally comprises a certain number of parts which are common to both types of auxiliary trip devices to be constituted. Other parts of the auxiliary trip device are on the other hand specific to the auxiliary trip device of the undervoltage release type and other different parts are specific to the auxiliary trip device of the shunt release type. Moreover, certain parts which are common to both these types of auxiliary trip device have to be mounted differently for the two types of auxiliary trip devices. The fact that a large number of parts are different between these two types of auxiliary trip devices constitutes a drawback since this leads to a relatively high manufacturing cost and an assembly cost which is also relatively high.